Direct-acting engine



(No Model.)

J. PRACY.

DIRECT ACTING ENGINE. N0. 362,855. Patented May 10, 1887 UNTTED STATESPATENT Cl nics,

JOSEPH PRACY, OF SAN FRANCISCO, CALIFORNIA.

DIRECT-ACTING ENGINE.

SPECIFICATION forming part of Letters Patent No. 362,855, dated May 10,1887.

Application tiled Deeemhvriil, 188G. Selial Nofil'lildfil.

T0 aZZ whom it may concern.-

ie it known that I, JOSEPH Prater, of the city and county of SanFrancisco, State of California, have invented an Improvement inDirect-Acting Engines; and I hereby declare the following to be a full,clear, and exact descrip tion of the same.

My invention relates to certain improvements in direct-acting engines,and is more especially applicable to that class of reciprocating engineswhich are employed to operate pumps.

It consists of a novel arrangement of a single valve with supply andexhaust ports and a mechanism by. which the valve is operated, all ofwhich will be more fully explained by reference to the accompanyingdrawings, in which- Figure 1 is a longitudinal vertical section of theengine adapted to drive a pump. Fig. 2 is a crossscctional view on theline a: a; of Fig. 1.

A is the steamcylindcr, having the piston B and the piston-rod C, whichin the present case is shown extending out through a stuffing-box in oneend of the cylinder and continuing into the pumpcylinder, where it coirnects with the pumppiston, which it actuatcs.

E is the valve chamber, which in thcpresent case is made cylindrical andcontains the valve, composed of two heads, F F, which lit the cylindersufliciently tight, and are connected by an intermediate shank,C-,ofsinaller diameter, the heads and shank being made hollow and openfrom end to end, as shown.

H H are steam-ports leading from the steam-chest to the ends of thesteam-cylinder A, and I 1 are exhaust-ports, the lower ends of whichopen into the ports H H, while their upper ends open into thesteam-chest or valvechamber at points nearer to the center, so that whenthe valve is moved to open one steamport, H, the other steam -port,H,will be closed, and the exhaust-port I will be closed by reason of thehead F covering it, while the exhaust-port I will be opened by the headF having moved so far as to expose it while closing the steam-port H.The alternate reciprocations of the valve thus open and close thesteam-ports and exhaust-ports, communicating with the space around thediminished (No model.)

shank G, the live-steam and exhaust connections being similar to thoseusually employed in this class of engines.

In order to balance the pressure through the ports from below the valve,I make openings J in the top of each of the heads, and as the steannhasfree access to theinterior of the valve the latter will be relieved bymeans of these openings J, which may bear any desired proportion to theopenings I 1 below. In order to actuate the valve, it has a stem,K,which passes out through a stuiiingbox above and parallel with themain piston-rod C, and this rod K has adjustable collars a fixed uponit. The end of the rod opposite to the valve enters a cushion-cylinder,N, being attached to a piston within that cylinder, as willbehcrcinafter described.

The collars a are situated about midway between the engine and pumpcylinder, and a sleeve, 0, traveling on guides, surrounds the rod Kbetween the collars a, the opening in the sleeve being so large that therod moves through it freely. Projecting downwardly from this sleeve arelugs 1?, having considerable space between them, and between these lugsthe upper ends of levers Q project. These levers Q, are'fulcrumed in theconnecting-yoke R, which extends between the engine and thepump-cylinder, or in other parts of the engineframe, and their lowerends are connected by links S with an arm T, which is secured to themain piston-rod C, as shown.

Upon the sleeve 0 is secured a short rack, U, and above this is apinion,V, which is fixed to a shaft between the disks \V. These diskshave crank-pins upon them, and they are connected by means of a rod orrods, X, with a piston, Y, moving within a pressure-cylinder, Z.

The operation of this device will then be as follows: The piston B inthe main cylinder A being in the position shown in the drawings, and thevalve in such position that the steamport H will be open, the head F ofthe valve will close the exhaustport I, and steam which has beenadmitted into the valve-chamber will pass through the port H into thespace behind the piston B, and, driving the piston in the directionshown by the arrow toward the righthand end of the cylinder, will movethe piston-rod O, the arm T, andthrough the connecting-link the leversQ. The upper ends of the levers are united by a cross-bar, and this actsagainst the downwardly-projecting lug P at the left end of the sleeve 0,thus moving it in a contrary direction from that of the piston B. Thiscarries the toothed rack U, which, acting upon the pinion V, turns itand the disks WV, the crank-pins of which act through the connectingrodsX to press the piston Y into the cylinder Z until the crank-pin hasreached a point above the horizontal line of the axis, or above thedead-center. The pressure from within the cylinderY will then completethe semi-rotation of the disks and the gear-wheel V, which, acting uponthe rack, will through it carry the sleeve 0 into contact with thecollar a, which is adjustable upon the rod K, and through it will forcethe valve F F to the opposite end of its stroke, the space between thelugs Iallowing the sleeve to move independent of the lever Q. Thereverse movement then takes place, the lever-arm Q acting to start thesleeve 0 in the same manner as before described, until theconnectingrods X of the piston Yare below the horizontal line takenthrough the axis of the crank- (lisks, when the piston Y will againcomplete the stroke in the opposite direction and return the valve.

The movement of the crank-disks WV is onehalf of a revolution, (more orless,) the points of rest being above and below the plane of the axisabout which they revolve, so that when the piston Y has been forced outof the cylinder Z to its point of rest the crank-pin of the disk will beeither below or above the shaft. The sleeve 0 and rack U are carried bythe lever Q to such a point that the piston Y can complete the movementin each direction, the lugs I? being so far apart as to allow a movementof the sleeve independent of the lever Q, as before described.v

The pressure which is applied to move the piston Y may be-that of acolumn of water, compressed air, or steam from within the engine itself.

In the present case I have shown a small connecting-passage, throughwhich steam is admitted into the cylinder Z from the valvechamber E; butvarious sources of pressure may be employed to actuate the piston Y, orto complete the rotation of the disks W,without altering the characterof my invention.

Within the cylinder N is a piston, b, which is connected with the rod K,and as the valve moves from one end to the other of its stroke thepiston b acts to cushion against the air contained in each end of thecylinder N, and thus prevent the valve from moving too far or strikingagainst the ends of the valve-chamber.

Openings are made in the the cylinder- N, through which the body of airwithin the cylinder may be maintained at its proper pressure.

Although I have here shown the pressurecylinder Z situated near theupper part of the valve-chamber, it will be manifest that its positionmay be changed, and that various well-known mechanical equivalents maybe employed to apply its power to the movement of the valve, as abovedescribed.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, isg 1. Ina direct-acting engine,areciprocating piston and piston-rod and the single reciprocating valvemoving within the valve-chamher and controlling the supply and exhaustports of the cylinder, in combination with a reciprocating sleeve, bywhich the valve is moved, a lever connected with the main piston-rod, bywhich the movement-of the sleeve is commenced, and crank or eccentricarms connected with the sleeve, and a pressure apparatus by which themotion of the'crank is completed after passing a dead center,substantially as herein described.

2. A sleeve moving over or with the valvevstem or its connectionsexterior to-the valvechamber, collars upon the val vestem, and a rackand pinion or intermediate mechanism between the sleeve and cranks,secured to a horizontal shaft connected with a piston moving in apressure-cylinder, substantially as herein described.

3. A sleeve moving over or with the valverod or its connections exteriorto the valvechamber, stops secured to the valverod, against which thesleeve may act, a toothed rack and pinion connecting the sleeve withcranks fixed to a shaft,.and connected with a piston moving in apressure-cylinder, as shown, in combination with a lever one end ofwhich acts upon lugs projecting from the sleeve, so as to start thevalve in either direction, while the other is connected with the mainreciprocating pis ton-rod, substantially as herein described.

4. In a direct-acting engine, the main cylinder,piston, piston-rod, andsingle reciprocating valve and connected supply and exhaust ports, andthe intermediate mechanism by which the movement of the val ve iscommenced and completed, as shown, in combination with thecushion-cylinder N and piston 1), moving IlO within said cylinder andconnected with the valve-stem, substantially as herein described. Inwitness whereof I have hereunto set my hand.

JOSEPH PRAOY.

Witnesses:

S. H. NoURsE, J. H. BLooD.

